1. Field
The present invention relates generally to a heat sink assembly being mounted on a printed circuit board, and more particularly to fasteners for mounting the heat sink assembly to the printed circuit board.
2. Prior Art
During operation of an electronic component such as a computer central processing unit (CPU), a large amount of heat is often produced. The heat must be quickly removed from the CPU to prevent it from becoming unstable or being damaged. Typically, a heat sink is attached to an outer surface of the CPU to absorb the heat from the CPU. The heat absorbed by the heat sink is then dissipated to ambient air.
Conventionally, a heat sink comprises a heat spreader and a plurality of fins extending from the heat spreader. The heat spreader is fastened on a printed circuit board by extending screws or bolts through holes defined in the printed circuit board. U.S. Pat. No. 5,757,621 shows an example of this kind of heat sink. The screws generally each comprise a head for facilitating an operation of the screw. The head defines a cutout therein to receive a fastening tool, such as a screwdriver. When the heat sink is assembled to the print circuit board, the screw is tightened relative to the printed circuit board by the screwdriver.
However, the actual assembly task of the heat sink is complicated by the greater density of components on the printed circuit board as less room around the heat sink is available to allow assemblers to screw the screws with the fastening tool. The assemblers must gingerly assemble the heat sink on the printed circuit board with the fastening tool. When a force applied to the screws by the fastening tool is diverted from its intended downwardly vertical direction, the screwdriver may slide away from the screw to impact and damage the other components on the printed circuit board.
When components are damaged by the fastening tool, the overall cost of the printed circuit board is increased as oftentimes the damaged components or even the printed circuit board must be replaced.
Hence, there is a need for an apparatus for attaching heat sinks to printed circuit boards in a manner which reduces the likelihood of damage to the components on the printed circuit board or to the printed circuit board and still ensures that the heat sink is properly mounted on the printed circuit board.